This is a Phase 1 STTR application entitled "Development of an ABO Incompatibility Stop Device" (hereafter AISD) to prevent mistransfusion. Mistransfusion, a term generally used to describe an episode where "the wrong patient receives the wrong blood", occurs for a variety of reasons including improper identification of the intended recipient during initial sample collection for blood typing, improper typing or pretransfusion testing of the blood component or recipient in the blood bank, or misidentification of the patient recipient and/or the blood unit at the time of initiation of the blood transfusion. Mistransfusion, considered by most authorities to be the leading cause of transfusion-related mortality, has a reported estimated incidence approaching 1 in 14,000 units in the United States. A number of technologies exist that are thought to be able to reduce mistransfusion including bar-coding of patient and blood unit identifiers, radio frequency identification (RFID), combination locked pouches that require a special bedside code, and bedside ABO tests that would allow an operator to retype the patient and match the patient blood type with the blood unit label. None of these methods has enjoyed even modest implementation to date, and each of these methods involves human actions, interpretation, or decision, thus allowing human error. It is human error, then, that leads to the #1 cause of transfusion-associated death. In this application, we describe novel fully automated, bedside medical device, the AISD, capable of: 1) performing a bedside compatibility test, and 2) preventing a mistransfusion event. This Phase 1 application is offered in a proof of concept format with preliminary data to support that both the concept of such a device and the proposed AISD design are feasible. The overall goal of Phase I is represented in a single Specific Aim: To design, test, and engineer a bench top prototype AISD consisting of 4 elements: the Red cell Exclusion Filter (REF), Compatibility Reaction Chamber (CRC), Incompatibility Detector (ID), and Stop Element (SE). Each of these 4 elements which constitute the AISD base unit will be designed, fabricated, tested, and optimized. This will be followed by building a working, bench top prototype that can be tested in a variety of clinically relevant circumstances (i.e., compatible transfusion combinations [O to A] and incompatible [A to O] combinations) in order to validate function and proof of principle. PUBLIC HEALTH RELEVANCE: While blood transfusions are life-saving interventions, sometimes incompatible blood is transfused in error and this can lead to death. In fact, this is the #1 complication of blood transfusion. A number of methods have been tried to improve this problem including better training of personnel and barcode identification of patients, but none has worked. In this application, we present a fully automated device that will sample the patient/recipient and the donor blood unit and prove compatibility without human assistance. If the unit is not compatible, the transfusion is not allowed to proceed. This should stop all mistransfusion and the related deaths. [unreadable] [unreadable] [unreadable]